1. Field of the Invention
The present invention relates to a method of setting conditions for a photographic printer, or more in particular to a condition-setting method for a photographic printer comprising a surface exposure section for print-exposing an image recorded on a developed photographic film to a light-sensitive material and a digital exposure section for print-exposing an image displayed on a two-dimensional display unit to the light-sensitive material.
2. Description of the Prior Art
A photographic printing apparatus (photographic printer) equipped with a paper processor for producing a print by developing the print-exposed paper is well known, in which each frame of an image recorded on a developed negative film is print-exposed on paper. In the photographic printer of this type, a proper print cannot continue to be maintained due to secular variations of the exposure light source or developer or the contamination of the light source. It is therefore necessary to renew the setting of the exposure conditions from time to time. Conventionally, in the case where the exposure conditions are set for the eletrophotographic printer, what is called a "Bull's eye" negative film corresponding to a negative film on which a circular gray object is photographed is used and print-exposed, and the density of the resulting test print is compared with a reference density to correct the exposure conditions. In the process, Bull's eye negative films of four different densities are used in order to produce a proper print regardless of the density of a particular negative film.
In recent years, a photographic printer has been proposed, which comprises a digital exposure section for print-exposing an image displayed on a two-dimensional display unit on paper in addition to a surface exposure section for print-exposing each frame of an image recorded on a negative film on the same paper. An example application of the digital exposure section is what is called an index printer in which several frames of image recorded in a unit of negative film are arranged in matrix and printed in compressed form. With the index printer, the images recorded in the negative film are read by a scanner, the data on the image thus read are displayed in an alignment of each several frames on a two-dimensional display unit. The displayed images are exposed for printing on paper at a predetermined timing, thereby producing an index in matrix.
Conditions for this digital exposure section are also required to be set in order to maintain a satisfactory quality of the final print. Despite of this requirement, a proper method of setting such conditions for the digital exposure section has yet to be established. A conceivable condition-setting method for the digital exposure section is, as for the surface exposure section, by using Bull's eye negative films of four different densities. This is a very complicated and time-consuming job, however, as it requires repetition of exactly the same process as the condition-setting for the surface exposure section.